CA1329631C - Method and apparatus for conveying materials in bulk by liquid pressure - Google Patents

Abstract

METHOD AND APPARATUS FOR CONVEYING MATERIALS IN BULK
BY LIQUID PRESSURE

ABSTRACT OF THE DISCLOSURE
A method for conveying materials in bulk by li-quid pressure carried out by an appropriate apparatus involves loading a material in bulk into a chamber through a loading pipe and then supplying liquid un-der pressure through a pipe for supplying liquid in the form of a downward annular flow, and discharging the material in bulk in an upward flow through a dis-charge pipe mounted to extend coaxially with, and inside the pipe for supplying liquid. A zone of recir-culation flows of liquid is formed in the chamber by swirling the annular flow to an extent determined by a ratio of the rotational component of velocity to the axial component of velocity at least equal to 0.4.
The material in bulk is discharged in the zone of reoir-culation flows. For swirling the annular flow, an inlet port of the pipe for supplying liquid is located in the periphery thereof, and the axis of this port is off set with respect to the axis of the discharge pipe. The inlet and outlet ports of the pipes for ma-terial discharge and liquid supply, respectively, are located at predetermined level with respect to each other.

Description

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- ~ield of the ~rt The invention ~elates to the conveyance o~ ma-terials by liquid pressure, and more specifically, it ~eals ulith a method and apparatus for conveyinO mate-rials in bulk by liquid pressure.
he invention may be advantageously us~d in the - mining ind~stry, construction, metallurgy a~d agricul-ture for a long-range conveyance of materials in bulk by liquid pressure.
It is especially interesting to make use of the invention for conveying materials in bulk by liquid pressure, in particular, in handling min~ral raw mate-rials, for the concentration and in working placer and ore deposits by open-pit and underground mining, ~or handling coal ~ines at thermal povJer plants, for con-veying concentration tails to stockpiling locations, for transporting rubbish materials and in the water engi-neering construction.
~he ^mployment o~ the method and apparatus ~or conveyin~ materials in bulk by liquid pressure is aimed at bringing a solution to the main problem of eliminatin~ contact of particles being conveyed with moving and flow-duct parts of a pressure unit so as to avoid their abrasive wear, tho use of much more power-`~g' ful water pumps to replace lo~-pressure slurry pumps and the conveyance of high-density slurrie 9 .
Background of the Invention Conventional conveyance of materials in bulk using slurry pumps is carried out with a slurry den-sity of maximum 15%. For a long-range conveyance, it is generally required to provide intermediate pumping stations which may be success~ully replaced by a single station consisting of a group o~ apparatuses for conveying matèrials by liquid pressure ~orkin~
alternately with one and the same pipeline with a single or with several water pumps to supply high-density slurry through the pipeline so as to enhance an overall throughput capa¢ity of conveyance.
g ~5 A number of requirements determined by a specilic charaoter o~ operation influencing economic e~fective-ness and reliability are ~enerally imposed upon such methods and apparatuses for conveying materials in bulk by liquid pressure.

2~ ~irst o~ all, reliability o~ methods ~or conve-ying by liquid pressure is determined by operation ` of apparatuses ~or carrying out such methods in the - discharge mode without clogging. ~he economic e~fecti-vene S9 0~ apparatuses for conveying materials in bulk by liquid pressure depends on density of prepared : slurry pumped into a pipeline, absence o~ density 1~29631 fluctuations during conveyance, minimum head losses in chambers o~ the apparatuses and the possibility of preparing and conveying by liquid pressure of slurry of uni~orm quality, grading and substance com-position. It should be noted that density o~ slurry is directly proportional to specific energy con-sumption for conveying materials in bulk by liquid pressure. The 9 pecific energy consumption depend 5 on losses o~ head developed b~ the pump in the chamber which are determined by the method of prepari~g and discharging slurry and also by position of a pipe s for supplying liquid under pressure and pipe for dis-charginæ the material in bulk.
~hree types o~ methods for conveying material~
in bulk by liquid pressure are now available in which the material in bulk is discharged in a downward ~low, in an upward flow, and in a horizontal ~low. ~he least reliab~e one is a method of discharging in the down~ard flow which is associated with frequent 20 clogging of the pipe for discharging the material in bulk and which is characterized by a low e~ficiency -of mixing of solid and liquid components in the cham-ber. The method of horizontally discharging is also accompanied by frequent clogging o~ the discharge 25 pipe and generally calls for the employment of bypass pipes which negatively affects density o~ prepared and conveyed slurry.
~he method of discharging slurry in the upward - flow is the most reliable one irom the point o~
- 5 view of clogging.
Ho~ever, each of the abovedescribed methods is s- charaoterized bg a continuous dearease in slurry density at the end o~ the discharge cycle during ope-ration.
In addition, during the cycle, when a material in bulk is supplied to the chamber with di~ferent quality and composition the discharge is also carried out ~enerally with non-uni~orm quality of the mate-- rial-without it~ homo~enization so as to reduce sta-bility of operation o~ a material handling system ;~ as a whole.
Enown in the art is a method ~or conveyi~g ma-terials in bulk by liquid pressure (SU,A,391974), com-prising loading a material in bulk into a chamber to fill it up, then supplying liquid under pressure simul-., taneously to the top part o~ the chamber and through ~- a b~pass pipe to the lower or bottom part o~ the chamber to mi~ liquid and sol~d components o~ slurry and to discharge the material in bulk in an inclined upward slurry ~low ~rom the chamber and to convey the slurry. Density of slurry being discharged is controlled "

bg increasing or decreasing quantity of liquid supplied under pressure to the bottom part o~ the chamber.
Known in the art is an apparatus for carrying out the method ~or conveying materials by liquid pressure (SU,A,391974), comprising a vertically ex-s tendin, chamber having a loading gate in the top part ~hereof.
A pipe ~or liquid draininæ is provided in the bottom part o~ the chamber and communicates with a perforated pipe accommodated in the chamber, and a . pipe ~or supplying liquid under pressure co~nected - to the pipe ~or liquid drainin~ by means o~ a bypass pipe is provided in the top part of the chamber.
A pipe for discharging the material in bulk i5 - provided in the bottom part o~ the chamber and has its end located above the chamber bottom, the draining - and discharge pipes having longitudinallg extendingports ~acing towards each other and closable by means o~ a slide ~ate.
The inclined position o~ the discharge pipe ~ cannot eliminate its clo3ging, especially ~Jhen wor-; king ~ith the closed slide gate. While it is possible to control density o~ slurry ~or maintainin~ it cons-tant, it is, however, impossible to achieve high den-: 1329631 sity values since the longitudinally extending ports should be le~t maximum open at the beginning of the dischar~e c~cle and, as the ports are located oppo-- site to each other, a part of liquid will be directed to the discharge pipe without entraining the material in bulk. At the end of the cycle, with the shut ports, liquid under pressure ~ill be supplied to the discharge pipe ~rom the top part of the ohamber which also causes a decrease in slurry density.
A change in flow o~ liquid under pressure supplied to the bottom part may be carried out either by a pump or by shiftin~ the slide ~ate. However, controlling liquid ~low by a pump cannot bring about a change in density o~ slurry prepared in this method.
A chanOe in density is e~fected by chan~inæ posi-tion o~ the slide gate with reapect to the ports.
~his i3, however, very difficult because o~ operation o~ the slide gate in a direction perpendicular with respect ~o the direction o~ liquid supply under pres-sure and respectively high dynamic loads whioh results in an additional energy consumption.
~ he discharge of slurry in the inclined upward flow in the abovedescribed method ~rom the lateral - part of the chamber cannot bring about homo~enization o~ the material in bulk in respect o~ ~rading and sub-stance composition.
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The provision of the bypass pipe in the apparatus and the supply of liquid under pressure alternately through a horizontal liquid supply pipe and through an inclined liquid draining pipe results in substan-tial head losses in the chamber in carrying out themethod which negativel~ afiects the range o~ conveyan-ce and overall energy power requirements of the method.
Enown in the art i9 also a method for conveying materials in bulk by liquid pressure (D~,A,3144~673, comprising loading a material in bulk into a chamber to ~ill it up, supplying liquid under pressure simul-taneousl~ to the top part of the chamber via a bypass pipe, and to the lower or bottom part o~ the chamber . 15 through a pipe for supplying liquid under pressure, oausing liquid to move along a helical guide member towards an inlet port o~ a discharge pipe for mixing ~lquid and solid components and for discharging the material ~n bulk from the chamber and conveying it .- zO by liquld pressure.
Enown in the art is an apparatus for conveying materials in bulk by liquid pressure, comprising a chamber having a frustoconical bottom and a pipe with a gate for loading a material in bulk a~ well as a bypass pipe having its upper end secured in the top 1329~31 -part o~ the chamber and its lower end conneGted to a pipe for supplying liquid under pressure. The liquid supply pipe is secu~ed in the bottom part o~ the chamber in such a manner that its outlet port is looated between the ohamber wall and an upright metal rod moun~ed at the center o~ the chamber bottom. ~he chamber is also provided with a pipe ~or disohaxging a material in bulk extending horizontally in the bottom part o~ the chamber bottom opposite to, and below the pipe ~or supplying liquid under pressure.
The apparatus also comprises a guide plate ~or washin~ oL~ and discharging the material in bulk ex-tendin~ around the upright rod along the conical sur-~ace of the chamber bottom, the upper part o~ the plate being attached to the chamber wall below the outlet port o~ the pipe ~or supplying liquid under pressure and the lower part of the plate being attached above '- the inlet port o~ the pipe ~or dischargin~ the mate-rial ~ bulk in the horizontal flow. A proteotive ba~le plate is provided above the outlet port of the pipe ~or supplyin~ liquid under pressure on the cham~er wall to prevent the outlet port ~rom being clogged with the ~aterial in bulk during loading.
The apparatus ~or carrying out the discharge ln the horizontal ~low cannot prevent clogging o~ the inlet port o~ the discharge pipe even with the pro-_g_ vision o~ the protective baffle plate. Special dif-ficulties arise with starti~g of the apparatus at the beginning of the cycle or after a sudden stoppage in the middle of the cycle ~he~ the Ouide plate and the conical bottom o~ the chamber are full of material in bulk up to the inlet port of the discharge pipe.
~ ixin~ of liquid and solid components in the abovedescribed method occurs at the phase boundary, namely between the bulk of the material being handled and the upper boundary o~ the starting portion o~ a high-velocity liquid flow movin~ helically within the chamber bottom around the rod towards the inlet port of the discharge pipe. Ohanges in density of slurry bein~ conveyed occur at the end of the discharge cycle only when additional liquid under pressure i9 supplied to the phase boundary by seepage ~rom the top part of the chamber, from the b~pass pipe.
~ owever, during conveyance of materials in bulk by liquid pressure through a large distance a high pressure and very high-velocity ~low passes through the chamber so as to cause low densities of prepared and conveyed slurry even if they are constant similarly to a hydraulic elevator. Therefore, the above-described method for conveying by liquid pressure e~-sures either an increased density of s?.urry or a largedistance of conveyance with a low density.

13~9631 With the material in bulk bein~ washed o~ ina co-current flow, it is not possible to ensure homo-- genization of the material in bulk discharged ~rom the chamber during the cycle so that the material i9 supplied into the c~nveying pipeline in the same order in which it YJas loaded into the chamber.
The provision o~ the bypass pipe, baf~le plate and ; guide plate ~or changin~ direotion ~or ~low causes sub-stantial head losses in the chamber which, ~or a given conveyance range, results in an increase in the pump power lnput and hi~her liquid velocity which negati-vely affects density o~ prepared and conveyed slurry.
The movement of a two-phase flow (liquid and solid in bulk) along a helical path on the narro~ing sur-~ace o~ the chamber bottom and about the rod also cau-ses hi;rh additional resistance which ne~atively a~-fects both density of slurry and overall energy consum-ption of the method as well.
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Enown in the art is also a method for conveying materials in bulk by liquid pressure (SU,A,1168496), comprising ~irst loading a material in bulk into a chamber to ~ill it up and then supplying liquid under pressure in the orm of a downward annular flow ~or dischar~ing the material in bulk ~rom the chamber - 25 in an upward ~low passin~ inside the downward annular ~low o~ liquid and conveyinO the material by liquid - pressure.

-~nown in the art is an apparatus ~or co~veyin~
materials in bulk by liquid pressure (SU,A,1168496), comprisin~ a chamber havin~ a pipe ~or loading a ma-terial in bulk, an upright liquid draining pipe, ;~ 5 a pipe for supplying liquid under pressure, and a pipe for dischargin~ the material in bulk in an up-ward ilow mounted coaxially with, and inside the pipe ~or supplying 1iquid under pressure.
- Carrying out the discharge o~`the material in bulk in the upward flow in a direction opposite to the direction o~ liquid supply under pressure into - the chamber allows the method to be carried out without clogging even upon a sudden stoppage of the pressure unit.
The discharge of the material in bulk in a strict-ly vertical flow a~oending ~rom the bottom part o~
the loaded chamber whereto the material in bulk i9 continually supplied under gravity makes it possible to increase density o~ prepared and conveyed slurry in comparison with the aoovedescribed methods. Xowever, mixing solid and liquid components by merely fluidi-- zing the material in bulk and by pumpinæ -the resul-tant slurry under a gauæe pressure cannot prevent density ~luctuations because o~ non-uni~ormity of supply o~ the material in bulk to the bottom part o~
the chamber. In addi-tion, density o~ the slurry being .:
conveyed will also var,y durin~ the entire dis¢harge cycle: it will have its maximum at starting with a certain decrease below the maximum value at the middle o~ the cycle while remaining almost unchanged and gradually decreaaing to zero at the end o~ the cycle.
~ his arrangement o~ the pipes for liquid supply under pressure in a downward flow and fQr discharging a material in bulk ensures uniform supply of the ma-terial in bulk to the inlet port oi the materialdischarge pipe in the zone therearound with a respec-,~ tive homogenization of the material in bulk duri~g the aischarge.
. ~he abovementioned iluidization of the material 15 occurs substantially over the whole space of the chamber 80 as to cause material head losses with a respeotive additional energy aonsumption.
In addition, pumpi~ the slurry into the pipefor discharging the material in bulk in this method occurs in the direction opposite to the direction oi liquid supply under pressure which also inevitably results in a hiæher speGiiic energy consumption.
Summary of the Invention It i9 an object of the invention to provide a method for conveying materials in bulk by liquid pressure which allows a 2-3-iold increase in density i ~329631 . .
o~ prepared and conveyed slurry to be achieved without a decrease in conveyance range.
- Another objeot o~ the invention ls to provide - an apparatus for conveying materials in bulk by liquid pressure which ensures a 2-3-fold increase in density of prepared and conveyed slurry without a decrease in oonveyance range.
Still another object o~ the invention is to provlde the possibility of controlling slurry density during conveyance by liquid pressure.
It is also an object oi the invention to ensure homogenization o~ the material in bulk in respect - o~ grading and substance composition durin~ prepara-tion a~d discharge of slurry.
Further object of the invention is to ensure minimum liquid head losses when liquid is supplied to the chamber for mixing liquid and solid aomponents and for disoharging slurry, hence, to optimize energy consumption.
These objects are accompl~shed by that in a method for conveying materials in bulk by liquid pres-sure, comprising loading a material in bulk into a chamber to fill it up and then supplying liquid under pressure in the form o~ a downward annular flow ~or disehargin3 the material in bulk from the chamber in .

an upward ~low passing inside the downward annular liquid ~low, and conveyin~ the material, aocording to the invention, a zone o~ recirculation ~lows of liquid supplied under pressure is iormed in the chamber by swirli~g the down~vard annular flow to a degree determined by a ratio o~ the rotational component o~
velocity to the axial co~ponent o~ velocity at least equal to 0.4, the material in bulk being diacharged in the zone o~ recirculation flows o~ liquid supplied : ~o unaer pressure.
It is pre~erred that in a method ~or conveying materials in bulk by liquid pressure accordin~ to the invention the size o~ the zone o~ recirculation ~10~JS of liquid supplied under pressure be controlled in a direction perpendicular to the direction o~
discharge of the material in bulk by varying pressure ~: of liquid supplied to the chamber duri~3 the discharge to a value at which liquid velocity corresponds to Re=3~10 .
. 2~ The above objects are also accomplished by that in an apparatus ~or conveying materials in bulk by liquid pressure, comprisin~ a chamber having pipes for loadin~ a material in bulk therein and ~or liquid drainin3, an upright pipe for supplying liquid under 25 pressure in a downward ~lo~, and a pip0 ~or discharging 1329~31 -.` the material in bulk in an upward ~low mounted ooaxial-ly wi-th, and inside the pipe for liquid supply, according to the invention, an inlet port of the pipe ~or supplyin3 liquid under pressure in a down-ward ~low is provided in the periphery thereof and has its axis oPfs~t with respect to the axis o~ the pipe for discharging the material in bulk in an upward Plow for swirling a dow~ward annular liquid flow in the space between the pipe for discharging the ma-terial in bulk in an upward flow and the pipe ~orsupplying liquid under pressure in a downward flow - Twith a preset flare an~le o~ the swirled downward annular liquid flow at the end thereof on the side of an outlet port, an inlet port of the pipe for dis-charging the material in bulk in an up~Jard ~low bein~
provided at one and the same level with an outlet port of the pipe ~or supplyin~ liquid under pressure in a downward ~low, below this level at any distance therefrom which is not ,reater than h1 determined h~ PW ~C
o . 6 ~ O (~
wherein Q 1s the ~10YJ of liquid sup?lied under pressure;
V is the velocity of the swirled down~lard annular ~low of liquid in the space between the pipes for supplying liquid under pressure in a do~nward flow and lor dischargin~ the material in bulk in an upward , ~1 ow;

1329~31 ~w i~ the density of liquid ~upplied under pre3-- sure;
i~ the den~ity of the material in bulk;
is the flare angle o~ the swirled downward , 5 a~nular flow of liquid;
g is the acceleration of gravity, or above this level at any distance there~rom which i~ not greater than h2 determined by the formula:
h2= ~ [0!372 + o!693 ~I (4 ~ + 5 R + 1) -_ Rl ln RR21 ~ ~~ ln wherein R is the radius of the pipe for dischargingthe material in bulk in an upward flow;
l is the amount of space between the pipe for supplyin~ liquid under pressure in a downward flow and for dis¢harging the material in bulk in an upward flow.
~ he apparatus according to the invention pre-ferabl~ aomprises a means for increasing the flare a~le o~ the swirled downward annular ~low o~ liquid provided at the end of one of pipes for supplying liqu~d under pressure in a downward flow and for discharging the material in bulk in an upward flow.
It is preferred that in an apparatus according to the invention the means ~or increasing the f~are angle of the swirled downward an~ular flow of liquid be made in the form of a diffuser.

,, It is pre~erred that in an apparatus according to the invention the means ~or inoreasing the ~lare angle of the swirled downward annular flow of liquid be made in the ~orm o~ a ring provided at the end o~
the pipe ~or discharging the material in bulk o~ the side o~ its inlet port.
~ he apparatus according to the invenbion pre~e-rably comprises a means ~or an additional swirling o~ the downward annular ~low o~ liquid provided in the spaoe between the pipes ior supplyi~g liquid - under preasure in a downward ilow and ~or discharging the material in bulk in an upward ilow.
In an apparatus according to the invention the means for an additional swirlin~ o~ the downward an-nular flow o~ liquid comprises a helical groove inthe inner surfaoe o~ the pipe ~or suppl~ing liquid under pressure in a downward ~low.
In an apparatus according to the invention the means ~or an additional swirling o~ the down~ard annular ~low of liquid pre~erably comprises guide vanes ri~idly secured to one of pipes ~or supplyi~g liquid under pressure in a downward ~low and ior discharging the material in bulk in an upward ~low.
- It is pre~erred that an apparatus according to 2~ the invention comprise a ~echanism ~or varying the relati~e position o~ the inlet and outlet ports o~ the , - pipes ~or discharging the material in bulk in an up-ward ilow and ~or supplyin~ liquid under pressure in a downward ilow, the mechanism belng linked with - one of pipes ~or discharging the material in bulk in an upward ~low and ~or suppl~ing liquid under pressure in a downward flow.
~ he method ~or conveying materials in bulk by liquid pressure according to the invention allows : the disoharge o~ a solid material to be carried out reliably and without clogging in an upward flow and in a zone of countercurrent supply of liquid under pressure into the chamber o~ the apparatus.
This method makes it possible to achieve a 2-3--~old increase in densit~ o~ prepared and conveyed slurry~
~irst of all, owing to the fact that liquid and solid components are mixed in a zone o~ recirculation li-quid ~lows ~ormed by swirling a downward annular li-quid ~lo~ which is characterized by high turbulence - and which ensures a much higher intensity o~ mixing .. ~0 o~ liquid and solid oomponents. The formation o~
this zone in the chamber provides ~or the creation o~ an area of lower velocities in the central part of the ~low o~ liquid supplied under pressure, and the disoharge o~ the material in bulk in this area prevents liquid supplied under pressure irom spreading over the full space of the ohamber so as to ensure -the admission o~ the major bulk of liquid and material being handled to this area whereby mixing o~ the components is materially localized and accelerated.
Density of the prepared slurry during the dis-charge o~ the material in bulk from the ¢hamber ge-nerally continually changes between maximum ~alues and zero, but this change occurs in steps rather than æradually. In oase of the upward flow disaharge, this is aaused by the iact that mixing of oomponents carried out by merely fluidizing the material in bulk is accompanied by a re~ular separation of a large mass o~ fluidized material ~rom the body o~ the mix-ture, the weight o~ the mass being sometimes greater than backpressure o~ liquid supplied to the chamber, and by the discharge oi thls mass alternating with the discharge o~ liquid batches. Density fluctuations are not ~ery high, but they take place.
In the method according to the invention, owi~g to the presence of a local zone o~ re¢irculation ilows, the process o~ discharge of the material in bulk is carried out continuously without density ~luctuation~
o~ prepared s~urr~ since separation oi the material - in bulk ~rom the rest o~ the mi~ture occurs through separation o~ particles with highly-turbulent vorti-ces of the local zone.
-2~--In addition, in carryin~ out the method, the material in bulk which is continually and gradually admitted to the zone o~ reairculation ~lows under - gravity and hydrostatia pressure o~ the overl~ing li-quid layers that displace the material in bulk ensures a more or less constant density o~ prepared slurry duri~g the entire cycle with a decrease in density by ~ the end o~ the cycle.
- ~he method according to the invention makes it - 10 possible not onl~ to increase density o~ prepared slurry without additional energy consumption, but also somewhat lo~ers powerrequirements ior the discharge of the material in bulk ~rom the chamber, other conditions being the same. The discharge is carried out in the area of lower velocities and with a ba¢kpressure ~rom the zone o~ recirculation ~lows so as to lower the aotin~ hydraulio resistance and to allo~ the range o~ conveyance by liquid pressure to be increased.
- 20 ~he method according to the invention, owin~
to the provision o~ the recirculation zone in which the discharge is carried out and which ensures a stable intensive mixing o~ solid and liquid compo-nents with hi3hly-turbulent vortices in a local zone ; 25 and uniform separation by the vortices o~ the ma-terial in bulk ~rom the rest of the mixture on all .
sides allows a higher degree of homogenization o~
the material in bulk to be achieved duringr prepara-tion o~ slurry and its discharge.
Controllin~ the size of the zone o~ recircula-tion ilows by varyin3 pressure of li~uid suppliedto the chamber in a direction perpendicular with re~pect to the direction of discharge o~ the ma-terial in bulk allows control o~ density o~ dischar~ed and conveyed slurry to be e~fected to keep it constant up to the end of the cycle.
It should be noted that a swirled downward annular flow of liquid passin~ through a chamber ~enerally undergoes a chan~e in the initial ratio o~ the rota-tional component of velocity to the axial component of vel~city to a certain extent which at the boundary of the zone o~ recirGulation flows should be at least equal to 0.4. With an increase in pressure o~ liquid bein~ supplied this ra-tio will change, i.e. the f~are anOle of the swirled downward annular flow will increase with a respective increase in the ~width of the zone of recirculation flow~ and area of contact of the material in bulk with this zone. ~he process o~ en-trai-nin~ the material in bulk with hi;rhly-turbulent re-circulation flov~s is thereb~ intensified to increase density of slurry bein, conveyed. ~he initial pressure o~ liquid supplied to the chamber is set up to be hi~h enough to carry out di~charge o~ the material in bulk and for conveying it to a desired range.
An increase in the ratio o~ the rotational compo-nent oi ~elacity to the axial component oi velocity with an increase in pressure will occur to a certain ; limit characterized by obtainin~ a steady sel~-simulating mode oi flow of the swirled downward annular flo~ of liquid in the chamber. This limit oorresponds to a velocity o~ flow of liquid supplied to the chamber which corresponds to the Reynolds ~umber Re=3-105.
As the possibili-ty of controlli~g density by varying liquid pressure is limited by the establishme~t oi the seli-simulating mode, the apparatus provides ior controllin~ densit~ over a wide range by varying the relative position oi the inlet and outlet ports - o~ the pipes ior discharging the material in bulk and ior supplying liquid under pressure in a down-ward ilow within the boundaries of -the zone oi recir-culation ilows.
In addition, the apparatus features a simple construction so that it only takes to ensure a tanæen-tial or chordal supply oi liquid to the space bet-~een the pipes for liquid supply under pressure in a downward ilow and ior dischargin~ the material in , bulk in an upward ~low to increase density o~ prepared and conveyed slurry.
- Positioning the pipe for discharging the material in bulk in an upward flow in the central part o~ the zone o~ recirculation ~lows which features lower velo¢ities o~ liquid bein~ supplied ensures swirli~g o~ the upward ~low o~ slurry being di~charged in the chamber upstream the inlet port of this pipe which also contributes to a reduction o~ head losses 10 dur~ng the discharge and lowers overall energy con-; sumption.
Brief Descliption o~ the Drawings The invention will now be described with reference to speci~ic embodiments illustrated in the accompanying <. 15 drawings, in which:
Fi~e 1 schematically shows a partial view, in lon~itudinal section, of a chamber with a loading unit illustrating a method for conveying by liquid pressure according to the invention;
20 Figure 2 is a ~eneral view,in longitudinal sec-tion,o~ a chamber sho~ing discharge and loading units according to the invention;
~igure 3 is a sectional view taken along line III-III in Figure 2;
Fi.,ure 4 is a general view, in lo~itudinal sec-tion, o~ a discharge unit having a dil~user provided ' ., at the end o~ a pipe ~or liquid supply;
Fi~ure 5 is ditto o~ Figure 4, but with a di~-fuser provided at the end of a pipe ~or discharging a material in bulk;
- 5 Figure 6 is ditto o~ ~ig~re 5t but with a rin~
provided at the end o~ a pipe ~or discharging a ma-terial in bulk;
Figure 7 i9 a general view, in a longitudinal section, of a discharge unit having a helical groove in the Lnner sur~ace of a pipe for liquid supply with a decreasing pitch according to the invention;
~ igure 8 is ditto of ~igure 7, with a groove having a constant pitch in the lower part of the liquid supply pipe according to the invention;
~igure 9 is ditto of Figure 7, with guide vanes provided on a liquid supply pipe according to the invention;
~ i,ure 10 i9 a partial general view, in lo~gi-tu~ æc~i~,o~ a discharge unit havi~ a mechanism for reciprocatin~ a liquid supply pipe according to the invention;
~ igure 11 schematically shovJs a general view of a plant ~or conveying materials in bulk by liquid pres-~ure incorporating two apparatuses ~or conveyance by 2, liquid pressure;
_,5_ Figure 12 show~ slurry density versu~ time during the discharge cycle for a. single chamber.
Detailed Description of the Invention A method ~or conveying materials in bulk by li-quid pressure comprises loading a chamber 1 (Fi3ure 1)with a material in bulk 2 to iill it up. The liquid in the form of a downward annular flow 3 is supplied to the chamber 1 under pressure thereby discharging the material in bulk ~rom the chamber 1 in an upward flow 4 passing inside the down~ard annular liquid flow 3, with subsequent conveyance of the resultant slurry by liquid pressure.
To increase density of the slurry being conveyed, lower po~er requirements for mixing solid and liquid components and for discharging the slurry, and to en-hance homogenization of the material in bulk during the discharge, a zone 5 of recirculation flow~ of liquid supplied under pressure is formed in the cham-ber 1, and for that purpose the downward annular liquid flow 3 is swirled to an extent determined by a ratio of the rotational component of velooity to the axial component of velocity at least equal to 0.4, the ma-terial in bulk 2 bein~ discharged in the zone 5 of recirculation flows o~ liquid supplied under pressure~
-26_ ~' ' ~ 1329631 .
To ensure the possibility of controlling density o~ prepared and conveyed slurry so as to prevent density irom decreasin~ at the end of the cycle, the - size o~ the zone 5 of reoirculation ~lows o~ liquid supplied under pressure is controlled in a direction perpendicular with respect to the direction o~ discharge o~ the ma~erial in bulk, and ~or that purpose pres-sure of liquid supplied to the chamber is varied ~rom the lnitial value to a value at which velocity ~ liquid supplied to the chamber corresponds to ~he Reynolds number Re=3-10 .
An apparatus for conveying materials in bulk by liquid pressure has the chamber 1 (Figure 2) that may have any desired con~iguration. It may be spherical, cylindrical, toroidal,and the like. One of the most advantageous con~i~ura-tions o~ the chamber ~o carr~
out the method is the toroidal con~iguration with vertical ¢yl~ndrical peripheral portions. The ohamber 1 has in the top part thereoi a pipe 6 ior loading the material in bulk which may be in the form o~ a loa-din~ pipeline ior loading the material in bulk in the form of slurry or in the iorm o~ a loadin~ hopper ha~in~ a ga~e ior supplyin~ a dry material in bulk to the chamber 1. The chamber also has a liquid drai-ning pipe 7 ior draining process water displaced duringloading. In this embodiment, the pipes 6,7 are mtegrated :
to form ~ loading unit 8 so as to enhance structuralstrength of the chamber 1 and to increase conveyance ran~e as well as to minimize losses of the material in bulk during loadi~g. The pipe 7 is provided with a sealing member 9 mounted at the end thereof outside the chamber 1, and the pipe 6 for loading the mate-rial in bulk is installed in the seali~g member. ~he chamber 1 has a discharge unit 10 consisti4g of two coaxially extending upright pipes 11, 12 for liquid supply under pressure in a downward flow and for discharging the material in bulk in an upward ~low9 res-pectively. The discharge unit 10 may be provided both in the bottom part o~ the chamber 1 if it is toroidal with the vertical cylindrical peripheral portions, the discharge unit 10 being provided therebetween at the upper point of the a~is of symmetry o~ the toroidal portion, and in the top part of the chamber 1.
The pipe 11 ior liquid supply under pressure in a down-ward flow has a sealing member 13 provided at the end thereof outside the chamber 1, and the pipe 12 for discharging the material in bulk in an upward flow is mounted in this sealing member. An inlet port 14 (F~gure 3) o~ the pipe 11 is provided in its periphery - below the sealing member 13 (Flgure 2) outside the chamber 1. To ensure swirling o~ the downward annular ~low 3 of liquid (Fi,ure 1~ in the spaG~ between the , 1329~31 . .
pipes 11 and 12 to an extent depending on a ratio o~the rotational component of velocity to the axial som-ponent o~ velocity at an outlet of the pipe 11 which is at least equal to 0.4 and which determines the flare an~le o~(Figure 1) of the swirled downward annular flow 3 o~ liquid, the axis 0 (Figure 3) of the port 14 is o~set with re9peot to the axis 0' of the pipe 12 in such a manner that the admission of liquid under pressure to the space between the pipes 11, 12 (~i~u-re 2) occurs either tan~entially o~ chordally so asto ensure a certain ratio of the rotational co~ponent ~- of velocity to the axial component o~ velocity.
With this construction o~ ~he discharge unit 10, : 15 the pipes 11, 12 have different lengths o~ their por-tions extendinæ inside the chamber 1. To increase den-sity o~ ~repared and conveyed slurry and to carry out the discharge of the material in bulk in the zone 5 o~ recirculation flows of liquid supplied under pres-sure (Fi~ure 1), the inlet port 14 (Figure ~) of the , pipe 12 for discharging the material in bulk in an . upward flow is located at one and the same level with - the outlet port of t~e pipe 11 (Figure 2) for supplying liquid under pressure in a do~nward flow, below this level at any distance therefrom which is not greater than h1 determined from the formula:

3 1~ ~V ~w co~
h ~I o 6:~ g (,Ja8-,~w ) -wherein ~ is the flow o~ liquid supplied under pres-sure;
V is the velocity o~ bhe ~wirled downward an-- nular ~low 3 o~ liquid in the space between the pipes 11, 12 ior supplying liquid under pressure in a downward ilow and for disohar-ging the material in bulk in an upward ilow;
is the density o~ liquid supplied under pres-sure;
~s is the density o~ the ~aterial in bulk 2;
is the flare angle ol the do~nward annular - swirled ~lo~ 3 o~ liquid;
g is the acceleration o~ gravi~y, or above this level at any distance thereiro~ that is not grea~er tha~ h2 determined from the iormula:

h2= ~ 0.372 + o!693 R2l (4 ~ + 5 R + 1) -(2) - ~I ln ~I ~ R- ln ~i] ' wherein R is the radius of the pipe 12 for discharging the material in buIk in an upward flow;
i9 the amount of space between the pipes 11, 12 for supplying li~uid u.nder pressure in a downward flow and for discharging the material in buIk in an upward flow~
~he value of the distance h1 i3 determined by condition that the inlet port of the pipe 12 be located in the zone 5 (Figure 1) of recirculation flows and by .
a special character o~ the aation of a consbrained submerged je~ and by the radius of curvature of the zone 5. The distance h2 determines position of the free boundary of the submer~ed jet in the ohamber 1 in which all flow o~ liquid supplied under pressure is admitted to the inlet porb o~ the pipe 12 (Figure 2) without entraining the ~aterial in bulk.
~ o achieve an additional increase in density o~
the prepared and conveyed slurry, the apparatus oompri-ses a means ior increasi~g the ~lare anæle o~ theswirled downward annular flow of liquid provided at the end o~ one o~ pipes 11, 12 ~or liquid supply and ~or discharge of the material in bulk. In the embodi-ment shown in Figure 4 this means comprises a diffuser 15 provided at the end o~ the liquid sup?ly pipe 11. In the e~bodiment shown in Fi~ure 5 the diLfuser 15 is provided at the end of the pipe 12 ~or disoharging the material in bulk.
Dimens~ons and angle of the diffuser 15 are de-s 20 termined by the desired ~lare angle oC o~ the swirled downward annular ~lo~ 3 o~ liquid in the cha~ber 1 ure 1).
In the embodiment shown in Figure 6, said means comprises a ring 16 provided at the end o~ the pipe 12 for discharging the material in bulk.
The rin~ 16 is designed ~or deflecting an ad-'' -ditional part oi the swirled down~vard ~low 3 (~igure 1) passing adjacent to the pipe 12 (~i~ure 6) and ~or increasin~ the ~lare anOle ~C (~i~ure 1) o~ the swirled flow in the chamber 1.
The use o~ both the dil~user 15 (Fi~ures 4,5) and the ring 16 (FiOure 6) allows the zone 5 o~ recir-culation ~lows o~ liquid ln the chamber 1 (Fi~ure 1) and the area of contact between the material in bulk ," and highly-turbulent vortices in the zone 5 to be enlarged,with a respective increase in density o~ the ' prepared and conveyed slurry.
-~, To achieve a hi,~her density o~ the prepared and , conveyed slurry and also to ensure a desired ratio ''~, o~ the rotational component of velocity to the axial . 15 component o~ velocit~ at the outlet of the nipe 11 ,, (~i~ure 2) in case the O~I set o~ the axis 0 (~igure ~) o~ the port 14 with respect to the axis 0' o~ the ~' pipe 12 cannot brinO about such an increase, a means ~or an additional swirlin~ ol the downward annular ~low o~ liquid is provided in the space between the ~ipes 11 and 12 (Fi,ure 2), The means ~or an additio~al swirlinO of the downw3rd annular ~lo~ in the embodiment shown in Fi~ures 7,8 comprises helical 3rooves 17,17' r;ith a pitch b in the inner sur~ace of the ?ipe 11.
The ~roove 17 (Figure 7) e.~tends alon~ the whole length of the pipe 11 with a gradual decrffase in the pitch b in the direction towards the outlet port, and the ~roove 17' (~iOure 8) is made in the bottom part o~ the pipe 11 adjacent to the outlet port the-reo~ and has a constant pitch b~ ~his constructionresults in an increase in density o~ prepared a~d con-veyed slurry owing to an increase in the ratio o~ the rotational component o~ vel~city to the axial compo-nent of velocity o~ liquid supplied under pressure to the axial component o~ velocity ensured by the abovementioned position o~ the port 14 (FiOure 3) ith respect to the axis 0' o~ the pipe 12 with a respective increase in the flare an~leo~of the ~ir~d downward annular flot~ 3 in the chamber 1.
~he additional s,wirling o~ liquid substantially increases turbulization of recirculation ~lows in the zone 5 and results in a hi~her degree o~ saturation o~ liquid with the material in bulk.
The means for an additional swirling o~ the down-ward annular flow of li~uid in the embodiment shown in ~iOure 9 comprises guide vanes 18 ri~idly secured to one o~ t~e pipes 11, 12. The vanes 18 have curved helical surfaces (similarly to a propeller), the an~le of curvature o~ their sur~aces determining, first o~ all, ths value o~ additional hydrauliG re-sistance appearing in the space between the pipes 11 -~3-12 with the provision of the guide vanes 18 and to a certain egtent a chan.ge in the ratio of the rota-tio~al component of velocity to the axial component '- of velocity.
, 5 ~he anæle o~ curvature o~ the helical sur~ace o~ the guide vanes 18 is determined to comply with the condition of minimizing the additional hydraulic resistance in the space between the pipes 11, 12. In . this embodiment the angle of curvature is between 8 j 10 and 15. The width of the guide vanes 18 is about - equal to the a~ount of space between the pipes 11, 12.
- To achieve the maximu~ swirling e~fect and to increase . the flare angle dC(~igure 1) of the s~;irled downward annular flo~ of liquid 3 at the outlet of the pipe 11 (Figure 9), the guide vanes 18 are provided on one of pipes 11, 12 adjacent to the outlet port o~ the pipe 11 at an angle ~ with respect to the axis of the pipe. The a~gle of inclination of the guide .~ vanes 18 is determined by the need to ensure a certain ratio of the rotational component of velocity to the axial component of velocity of the flow of liquid sup-plied under pressure, and this angle is between 60 and 30 in this e~bodiment, depending on kind of a material in bulk bein~ handled.
- 25 The guide vanes 18 are provided in an equall~
spaced relation to one another over th0 entire cross-seation o~ the space between the pipes 11, 12. ~he number of the vanes depends on the need to obtaLn a certain flare angle of the swirled down~ard annular f~ow of liquid at the outlet of the pipe 11. It has been found that for the construction of the apparatus described herein, ~ith guide vanes 18 mounted at an an~le ~ of 45 ~Jith respect to the a~i6 of the pipes 11, 12, the guide vanes 18 cover more than 5~%
of the live cross-section oi the space between the pipes 11, 12 so that they cannot bring about any re-markable increase in slurry density. The best result was achieved with six vanes 18f ~here~ore, with the ! provision of the grooves 17 (Figure 7), 17' (Figure 8) or vanes 18 (Fi~ure 9), the size of the zone 5 (~iOure 1) o~ recirculation flows increases to enhanca turbulization of the recirculation flows, and an in--: crease in the area of contact between the material in bulk 2 and the highly-turbulent vortices in the zone 5 of recirculation flows oi liquid ensures a high degree oi intensiiioation of mLxing of solid - and liquid components ~ith a respective increase in : density oi prepared and conveyéd slurry.
~ o ensure control of density of prepared and conveyed slurry at the end of the discharge cycle by varying the relative position of the outlet port o~
the pipe 11 (Figure 2) and the inlet port o~ the .
pipe 11, one of pipes 11, 12 i9 connected to a mecha-nism 19 (~iO~ure 10) ~or varying the relat~ve positicn of the inlet and outlet ports of the pipes for dischar-ging the material in bulk in an upward ~low and for supplying liquid under pressure in a downward flow.
In this embodiment, the meohanism 19 ensures axial movement of the pipe 11 along the pipe 12 and co~pri-ses a widely known cam mechanism. ~he mechanism 19 ensures mo~e~ent within the limits of the above-described distances h1 and h2 between the outlet portcf the pipe 11 and the inlet port of the pipe 12.
change in their relatiYe position determines the point of dischar~e o~ the material in bulk ~rom the chamber 1 (~igure 1) in the form of slurry within the zone 5 of recirculation flows. It should be noted that the lower the position of the inlet port of the pipe 12 at the end of the cycle with a small quantity o~ the material in bulk available in the cham~er 1, the higher is the degree of saturation ol the recir-culation flows in the zone 5 with the material in bulkand the lower is a chan~ge in density of prepared and conveyed slurry.
~ he pipes 6,7,11,12 (~igure 11) are connected to a slurry supDly pipeline 2~, drain pipe1ire ~l, pressl~re - 25 water supply pipeline 22, and conveyin-, pipeline 23, respectiYely.

~329631 The apparatus ~or conve~ing materials in bulk by liquid pressure is part o~ a plant ~or conveying - materials in bulk by liquid pressure. For operation on a continuous basis, this plant comprises a pair o~ such apparatuses oreven more, each communicating, throuæh the slurry supply pipeline 2~ having a built--in check valve 24, with a low pressure slurry pump 25 and, via the drain pipeline 21 having a gate 26, with a sump pit 27 of the law-pressure slurry pump 25 to avoid eventual losses o~ the material in bulk, and, via the pressure water supply pipeline 22 having a bu~t-i~ gate 28,with a hi~h-pressure water pump 29, and also communicates ~iith the conveyance pipeline 23 havinæ a check valve 30.
The appar3tus for oonveyin~ materials in bulk by liquid pressure ~unctions in the following manner.
The material in bulk in the ~orm o~ slurry is loaded by means o~ the low-pressure slurry pump 25 (Figure 113 - into the chamber 1 iilled .vith liquid replacing the material in bulk that has been conveyed during the ~oregoing cycle beiore fillinJ up the chamber. ~he ~- material in bulk is stored under gravity in the cham-- ber 1 to displace the liquid available in the chamber through the drain pipe 7 and drain pipeline 21 to the sump pit 27. ~he material in bulk is loaded into - the chamber 1 (FiOure 2) to a level o~ the outlet port o~ the loading pipe 6. When the loading cycle is over, the pipes 7 and 6 are shut off by the check-valve 24 (Figure 11) and gate 26, respectively, and liquid is supplied by the high-pressure water pump 29 through the pressure pipeline 22 and the inlet port 14 (Figure 3) of the pipe 11 for liquid supply under : pressure in a downward flow to the space between the pipes 11, 12 so as to swirl the annular flow 3 of liquid (Figure 1). A certain ratio of diameter~ of the pipes 11, 12 (Fi,ure 3) and the amount of space 1 ; tkerebetween ensures,with the tangential or chordal addmission of liquid, a flare angle ~C of the ilow at . the outlet of the pipe 11 whioh is determined by a ratio of the rotational component of velocity to the axial component of velocity at least equal to 0.4 so as to form the zone 5 of recirculation flows. ~he provision of the zone 5 of recirculation flows at the outlet of the pipe 11 (Figure 2) results in high flow velocities at the bounlary of flare-up o~ the swirled downward annular flow of liquid in the chamber 1 : (Fi~ure 1) and in the formation of an area of low ~elocities or-an area of countercurrent in the central part of the flow 3 so as to bring about a substantial . localization of the zone 5. The slurry is discharged in the central part of the zone 5 of recirculation ~lows of liquid through the pipe 11 (FiOure 2) ior ~ -3~-:

132~631 discharging the slurry in an upward ~low so as to ensure the admission o~ the major bulk o~ the liquid being supplied bo the inle~ port of the pipe 11 rather than movement of the liquid over the entire space o~ the chamber 1. Density of prepared and conveyed slurry is thereby increased by a factor o~ 2 to 3 owing to the in~ensi~ication o~ mixin~ o~ liquid and solid components in the localized zone 5 o~ recir-culation liquid ~low~ (Figure 1) since separation and removal o~ the material in bulk 2 from the rest o~ the mixture available in the chamber 1 oacurs at a hi~h velocity with hi,hl~-turbulent vortices of liquid in the zone 5 which are directed to~Jards the inlet port of the pipe 12 (~igure 2).
It is known that the material in buIk 2 (Figure 1) is conveyed by liquid pressure in the upward ~low 4 in the ~orm Or a swirled ~lo~,with the major body oi the material 2 being concentrated in the central parb o~ the flow 4. ~here~ore the discharge is gene-rall~ accompanied by additional head losses ior the formation o~ such a flow in pipes or pipelines. ~he zone 5 o~ recirculation liquid ilows ~ormed in the chamber 1 during the discharge b~ the material in bulk in the central part o~ this zone 5 ensures ~ormation ~ the swirled upward ~low 4 o~ slurry with a high concentration of the material in bulk already within the chamber 1 and dire¢tly upstream the inlet port o~
the pipe 12 (~iaure 2) which, with the coaxial posi-tion o~ the pipes 11, 12, minimizes hydraulic resis-tance in the pipe 12. It should be noted that slurry is not discharged i~ a direction opposite to that in ~hich liquid is supplied under pressure, but rather in the area o~ lower velocities or countercurre~ts which also contributes to lowerinæ Or power require-ments for conveying the material in bulk by liquid pressure. ~uring the disoharge, the material in bulk 2 (Fi~ure 1) gradually moves down without brid-ging and is uni~ormly entrained on all sides with highly-turbulent vortices of the zone 5 o~ recircula-tion ~lows to be intensively mixed therein so as to ensure homo~enization of the material in bulk ln respeot of grading and suhstance composition in car-ryin~ out the method aocording to the invenbion.
~herefore, owing to the intensive mixi~g o~
liquid and solid components with highly-turbulent vortices o~ the zone 5 of recirculation rlows, a slurry having a constant density during almost the entire discharge cycle period i9 prepared and conveyed.
It should be noted that at the end of the cycle, when pressure of the material in bulk and liquid layers - 25 above the zone 5 i9 substantially l~wer than those at the beginni~g of the cycle, slurry density gradually decreases to zero. ~o keep slurry density at one and the same level during the entire cycle, the ilare angle vC of the swirled downward annular flow 3 of liquid at the outlet of the pipe 11 (Figure 2) and, respectively, the size o~ the zone 5 of recircula-tion flowY (~i~ure 1) are varied, and for that pur-pose, pressure of liquid supplied to the chamber 1duri~ the discharge is varied. Consequently, at the end of the cycle, pressure is raised with a res-pective increase in the size of the zone 5 so that, in the end o~ the day, area of contact of the highly-turbulent vortices ~ith the matierlal in bulk 2 increa-ses and de~ree of their saturation with the material in bulk also lncreases owin3 to a decrease in the ~- velocity of vortices admission directl-J to the inlet port of the pipe 12 (FiOure 2). A change in the initiall~ set ratio of the rotational component of velocity to the axial co~ponent of velocity occurs as a result of h~draulic resistances in the space bet-ween the pipes 11, 12 during the pasiage of the s~irled liquid flow tnerein. With an increase in the flow velocity upon a pressure increase, the effect o~ roughness of the walls of the pipes 11, 12 on the change in the ratio of the rotational component o~
velocity to the axial co~ponent o~ velocity decreases.
With velocities corresponding to, or hiOher than those correspondin~ to the Reynolds number Re=3-1~5 in the port 14 (~igure 3), this ratio will remain unchanged ~/-r1 -.
upon a pressure increase since hydraulic resistance in the space will no longer afiect the ~lare angle~C
(FiOure 1) of the swirled flow, and a se~-simulatin~
~ ~low mode will obtain.
- 5 To ensure an additional increase iLl density oi slurry, the means ~or increasin~ the ~lare angle o~ the swirled annular liquid ~low is provided at the end of the pipes 11, 12 (~igure 2). Thus, -this means comprisinO the diffuser 15 (~igure 4) is provided at the end of the pipe 11 for supplyin~ liquid under pressure in a dol~-;nward flow. The swirled annular ilow has a larger flare angle at the outle-t of the dif-fuser 15, but the velocity of swirling of the ~low decreases as a wnole, and the differential of velo-cities between the boundary of the ~low and the centralpart thereoi decreases with a respec-tive reduction ~ ~ the velocity oi removal of the material in bulk ~ro~ the chamber 1 (Fi,ure 1) so as to impair conditi-ons for preparin~ an upward ilow of slurry in the chamber. Therefore, a certain increase in density of prepared slurry is achieved witr. a lo~i intensity of mixinO o~ liquid an~ solid components owin~ to ~
` larger area of contact between the zone 5 of recir-: culation flows of liquid and material in bulk. By providing ~he diffuser 15 (Fi,ure 5) at the end of the pipe 12 on the siae of its inlet port, the flare .

angleOC of the swirled downward annular ~low 3(Fi,~ure 1) and the width of the zone 5 Or the recir-culation flows are increased thereby enhancing the density of slurry being conveyed. The provision o~ the ', 5 diffuser 15 at the end of the pipe 12 aifects the velocity differential at the inle~ port thereof to a ,, smaller extent with a low~r effect on formation of ,~, the upward flow of the material in bulk bei~g dischar-ged adjacent to the inlet port of the pipe 12.
". 10 A hi~her densit~ of slurry may be achieved by : changin~ the flare angle of the swirled downward flow if the ring 16 (Fi~ure 6) is provided at the end of the pipe 12 on the side o~ its inlet port without chan~ing intensity of mixing of liquid and solid co~-ponents. However, the provision of the ring 16 causes additional hydraulic resistances which brings about an increase in overall power requirements for the , conveyance by liquid pressure.
- Density of slurry is increased by intensifyi4g '~ - 2~ mixing of liquid and solid components simultaneously with an lncrease in size of the zone 5 of recircula-' tion flows (Fi,,ure 1), and for that purpose the means ' ior an additional swirlin~ of the downward annular '~ liquid flow is provided in the space between the pipes 11, 12 (~iOure 2). ~hus, the means for an ad-..
-ditional swirling may be, e.g. in the form o~ the helical grooves 17, 17' (Fi~ures 7,8) in the inner sur~ace of the pipe 11 havin~ a pitch b. The helical - groove 17 (Figure 7) exbends along the whole length Gi the pipe 11 with a pitch b dec~easinæ in the di-rection to~Jards the outlet porb o~ the pipe 11, and the groove 17' (Figure 8) extends in the lower part of the pipe 11 and has a constant pitch b. These options are determined by length and dimensions Or the pipes 11, 12 and by a manu~acturing process avai-lable. The pitch b determines the degree of change in the ratio of the rotational component o~ velocity to the axial component o~ velocity during passage o~
the swirled downward flow through the space between the pipes. It should be noted that not only is a larger flare angle ~C (~i~,ure 1) of the swirled ilow obtained at the outlet o~ the pipe 11, but the degree o~ t-lrbulization o~ the recirculation ~l~ws is sub-stantially higher. ~his materially intensi~ies mixing cO o~ the material in bulk and contributes to a greater extent to the formation o~ a hi~h-density upward ~low o~ slurry in the chamber with a respective lowe-ring of power requirements.
~J~ith a large space between the pipes 11 and 12 (~igure 2) and with a high liquid ~lo~, the ~eans ~or an additional swirlin~ comprises the guide van~s 18 ~;

~329~31 ~, ure 9) rigidly secured to one o~ pipes 11, 12.
~he additional swirling ensures maximum increase in - turbulence o~ the ~low of liquid supplied to the chamber 1 (Figure 2) and maximum intensity oi mixing oi liquid and solid co~ponents. ~owever, the separation oi the downward annular ~l~w 3 oi liquid (~igure 1) during passage through the vanes 18 (~iO~ure 9) into individual flo~s and the provision o~ the vanes 18 in the space between the pipes 11 and 12 cause addi-tional h~draulic resistances at the admission o~
- quid to the chamDer 1 (~i~ure 2) which negatively a~fects overall power requirements o~ the method o~
.- conve~in~ the material in bulk by liquid pressure.
In applica~ions where it is not possible to cont-~A 15 rol density oi slurry within the abovementioned ve-locity ran~e because of conveyanoe conditions (with high flow and pressure parameters of operation of the apparatus with a long-ran~e conveyance), control is efiected by varying the relative position of the inlet and outlet ports o~ the plpes 12 and 11 (~i-gure 10) for dischargin3 the material in bulk in an upward flow and ior supplying liquid under pressure in a downward flow. For that purpose, the me¢hanism 19 is provided at one end of the pipe 11 or 12, and in this specific embodiment the mechani~ 19 i9 ., provided on the pipe 11. For varying ~he relative ..position oi the outlet and inlet ports of the pipes 11, 12 by axially reciprocating one oi them, the mechanism 19 may be in the iorm of a conventional cam meoha~ism 5 provided on the pipe 11. Ii the outlet port oi the pipe 11 is moved up at the end of the cycle, the velocity dii~erential oi the swirled downward annular ilow supplied in the area oi the inlet port oi the pipe 12 dec~eases with a respective increase in dura-tion oi the period duri~g which the recirculation -ilows oi liqu~d are saturated with the material in b~lk beiore the upward slurry ilow is ior~ed, and .slurry density increases. me mechanism 19 ~ay also :~.comprise tips on the ends of bhe pipes 11, 12 moved . 15 by hydraulic cylinders.
'The method and apparatus for conveying materials by liquid pressure according to the invention ~eatu~e..
reliability in operation and simple structure and allows density of prepared and conveyed slurry to be increased by a iactor oi 2 to 3 without dec~easin~
the conve~ance range and witn optimum power require--~ ments.
:For example, wit~ swirling of a do-wnward annular .~ilow oi liquid to an extent determined by a ratio of the rotational component of velocity to the axial component of velocity between 0.78 and 1.8 density .

of prepared and conveyed slurry conveyed through adistance of 6 to 8 km and containing a material in - bulk having a speci~ic gravity o~ 2.7-2.8 tfm3 ran~ed from 1.28 to 1.43 t/m~ ior di~erent discharge unit designs. Maximum density was obtained in using the guide ~anes mounted at the angle ~ =30. With the angle ~ =45, density o~ slurry being oonveyed w~
as high as 1.53 t/m3, but a substantial pressure decrease oacurred in the discharge unit (about 5%).
In another embodiment, wi-th the throughput oapacity o~ 300 m3~h when the same materia~ was conveyed through a distance o~ 3 km, velocity oi flow of liquid supplied u~der pressure was characterized by the Re~nolds number Re=5.3-105 80 that density in this case was controlled by means o~ the reciprocating mechanism ror moving the pipe ~or supplying liquid under pressure in a downward ~low.
For a better understandi~ o~ the method ~or con-veying material in bulk b~ liquid pressure, ~igure 12 showa density o~ slurry versus time durin~ the discharge cycle ~or a single chamber, in which time in seconds is plotted on the absciasae and density ~p in kg/m3 is plotted on the ordinates.
A gradual decrease indensity o~ slurry being conveyed shown in Figure 12, curve 31, occurred be-~
ginnin~ from about the middle o~ the c~cle with a sudden decrease at the moment t1~ When the pipes were moYed, the density o~ slurry prepared and con-veyed by the apparatus remained substantially unchan-ged during the last one-fi~th o~ the entire cycle (curve ~2). There~ore, with the utilization o~ the substantially all use~ul space of the chamber, the - discharge cycle was interrupted at the moment t1 f a material dec~ease in density, and a change-over was carried out ~rom one chamber 1 (~igure 11) to the other in the working mode so as to guarantee a cons-tant density versus time.
~ he use of the method according to the invention allouJs a material in bulk to be homo~enized in respect ~ gradi~ and substance composition, and the employ-5' ment of the apparatus according to the invention minimizes head losses ~or mixing liquid and solid components and ~or the discharge o~ slurry 1n an up- -ward ilo~J.

Claims (10)

1. A method for conveying materials in bulk by liquid pressure, comprising the steps of:
- loading a material in bulk into a chamber to fill it up;
- supplying to the chamber liquid under pressure.
in the form of a downward annular flow for discharging the material in bulk from the chamber in an upward flow passing inside said downward annular flow of liquid and conveying the material in bulk by liquid pressure;
- forming in the chamber a zone of recirculation flows of liquid supplied under pressure by swirling said downward annular liquid flow to an extent deter-mined by a ratio of the rotational component of ve-locity to the axial component of velocity which is at least equal to 0.4;
- carrying out said discharge of the material in bulk in said zone of recirculation flows of liquid supplied under pressure.

2. A method for conveying by liquid pressure ac-cording to claim 1, comprising:
- controlling the size of said zone of recircula-tion flows of liquid supplied under pressure in a direction perpendicular to the direction of said discharge of the material in bulk by varying pressure of liquid supplied to the chamber during said discharge to a value at which velocity of liquid corresponds to Re=3?105.

3. An apparatus for conveying materials in bulk by liquid pressure, comprising:
- a chamber for forming a mixture of a material in bulk and liquid therein for subsequent conveyance by liquid pressure;
- a pipe for loading the material in bulk through which said chamber is filled up with the material in bulk;
- a pipe for liquid draining through which liquid displaced by the material in bulk is removed from said chamber;
- an upright pipe for supplying liquid under pres-sure in a downward flow through which liquid under pressure is supplied to said chamber for washing the material in bulk with the formation of a slurry, the pipe having a periphery an inlet port, and an outlet port;
- a pipe for discharging, the material in bulk in an upward flow mounted to extend coaxially with, and inside said pipe for supplying liquid under pressure in a downward flow, the resultant slurry being removed and conveyed by liquid pressure through this pipe;

- an annular space between said pipes for sup-plying liquid and for discharging slurry, respecti-vely;
- said inlet port of said pipe for supplying liquid under pressure being provided in said periphery thereof and has its axis offset with respect to the axis of said pipe for discharging the material in bulk for swirling the downward annular flow of liquid in said space between said pipes for liquid supply and slurry discharge with a predetermined flare angle of the swirled downward annular flow of liquid at the end thereof on the side of said outlet port;
- the inlet port of said pipe for discharging the material in bulk being located at one of levels with respect to said outlet port of said pipe for supplying liquid under pressure ranging from a lower level to an upper level, wherein the lower level is located below the level of said outlet port of said pipe for supplying liquid under pressure at a distance therefrom which is not greater than h1 determined from the formula:
, wherein Q is the flow of liquid supplied under pressure;
V is the velocity of the swirled downward an-nular flow of liquid in the space between the pipes for supplying liquid under pressure in a downward flow and for discharging the material in bulk in an upward flow;
?W is the density of liquid supplied under pressure;
?S is the density of the material in bulk;
? is the flare angle of the swirled downward annular flow of liquid;
g is the acceleration of gravity, and the upper level is located above the level of said outlet port of said pipe for supplying liquid under pressure at a distance therefrom which is not greater than h2 determined from the formula:

, wherein R is the radius of said pipe for discharging the material in bulk;
1 is the amount of said space between said pipes for supplying liquid and for discharging the material in bulk.

4. An apparatus according to claim 3, comprising:
- a means for increasing the flare angle of the swirled downward annular flow of liquid provided at the end of one of said pipes for liquid supply and for discharging the material in bulk on the side of said outlet and inlet port, respectively.

5. An apparatus according to claim 3, comprising:
- a means for an additional swirling of the down-ward annular flow of liquid provided in said space between said pipes for supplying liquid and for dischar-ging the material in bulk designed to increase the ratio of the rotational component of velocity to the axial component of velocity.

6. An apparatus according to claim 3, comprising:
- a mechanism for varying the relative position of said inlet and outlet ports of said pipes for dis-charging the material in bulk and for liquid supply connected to one of said pipes for discharging the ma-terial in bulk and for liquid supply designed for lowering the effect of velocity differential adjacent to said outlet port of said pipe for supplying liquid on velocity of supply of the material in bulk to said inlet port of said pipe for discharging the material in bulk.

7. An apparatus according to claim 4, wherein said means for increasing the flare angle of the swirled downward annular flow of liquid comprises a diffuser.

8. An apparatus accordion to claim 4, wherein said means for increasing the flare angle of the swirled downward annular flow of liquid comprises a ring provided at the end of said pipe for discharging the material in bulk on the side of said inlet port thereof.

9. An apparatus according to claim 5, comprising:
- an inner cylindrical surface of said pipe for supplying liquid;
- a helical groove in said inner cylindrical surface which constitutes said means for an additional swirling of the downward annular flow of liquid.

10. An apparatus according to claim 5, wherein said means for an additional swirling of the downward annular flow of liquid comprises a plurality of guide vanes rigidly secured to one of said pipes for sup-plying liquid and for discharging the material in bulk.